Abnormality judgment method for pressure sensor of air inlet system under steady-state working condition

Abstract

The invention discloses a method for judging abnormity of a pressure sensor of an air inlet system under a steady-state working condition, which comprises the following steps of: when a judging condition of a stable working condition of inlet pressure of a throttle valve is met, acquiring an average value of inlet pressure of the throttle valve and an average value of outlet pressure of the throttle valve within a preset time; and according to the throttle valve inlet pressure average value, the throttle valve outlet pressure average value and a self-learning correction coefficient, whether the throttle valve inlet pressure signal breaks down or not is judged. The method provided by the invention can identify whether the pressure signal is abnormal or not under the steady-state working condition.

Description

Technical Field

[0001] The present invention relates to the technical field of engine control, and in particular to a method for judging abnormality of an intake system pressure sensor under steady-state conditions. Background Art

[0002] As the core information of intake control, the pressure sensor signal needs to identify whether the pressure signal is abnormal under steady-state conditions, so as to provide early warning and avoid damage to the engine and personal safety due to abnormal engine control.

[0003] The patent with application number 202110982953.2 discloses "A throttle flow calculation method, device, equipment and readable storage medium". The patent proposes to use the throttle pre-pressure (inlet pressure) and post-pressure (outlet pressure) to estimate the EGR flow, but does not propose a method for judging the abnormality of the intake system pressure sensor under steady-state conditions.

[0004] The patent with application number 202110518171.3 discloses "A method for measuring EGR mass flow, a measuring device and an exhaust gas treatment system". The patent proposes to use the pre-throttle pressure (inlet pressure) and post-throttle pressure (outlet pressure) to estimate the EGR flow, but does not propose a method for judging the abnormality of the intake system pressure sensor under steady-state conditions. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a method for judging abnormality of intake system pressure sensor under steady-state conditions in response to the deficiencies of the prior art. The method can identify whether the pressure signal is abnormal under steady-state conditions, thereby providing early warning to avoid damage to the engine and personal safety due to abnormal engine control.

[0006] To achieve the above object, according to one aspect of the present invention, a method for determining an abnormality of an intake system pressure sensor under a steady-state condition is provided, comprising:

[0007] When the throttle inlet pressure stable working condition judgment condition is met, the average value of the throttle inlet pressure and the average value of the throttle outlet pressure within a preset time are obtained;

[0008] Whether a throttle inlet pressure signal fails is determined based on the throttle inlet pressure average value, the throttle outlet pressure average value and a self-learning correction coefficient.

[0009] In the above scheme, the specific method for determining whether the throttle inlet pressure signal is faulty is:

[0010] When the throttle inlet pressure stable condition judgment condition is met, obtain the average throttle inlet pressure within the preset time t3 Average throttle outlet pressure

[0011] like It is determined that the throttle inlet pressure signal is faulty, otherwise it is determined that the throttle inlet pressure signal is not faulty.

[0012] In the above scheme, r Adpt It is the self-learning correction coefficient, the default value is 0, and it can be saved when the vehicle is powered off.

[0013] In the above scheme, the self-learning correction coefficient r Adpt The method for obtaining is as follows: record the number of times CNT3 that the throttle inlet pressure stable working condition judgment condition is met, and record the number of times CNT3 that the throttle inlet pressure stable working condition judgment condition is met. The number of times CNT4 is recorded after the throttle inlet pressure meets the stable working condition judgment condition The number of times CNT3, CNT4 and CNT5 are updated at most once in each driving cycle of the vehicle;

[0014] If CNT3≥200, CNT4≥160, and CNT5≤10, then r Adpt =r Adpt (z) -0.01;

[0015] If CNT3 ≥ 200, CNT4 ≤ 10, and CNT5 ≥ 130, then r Adpt =r Adpt (z)+0.015;

[0016] In other cases, r Adpt =r Adpt (z);

[0017] where r Adpt (z) is the self-learning correction coefficient of the last update; when CNT3 ≥ 200, then the self-learning correction coefficient r Adpt After the update, CNT3, CNT4 and CNT5 are reset to 0, and the counting starts again when the next condition is met.

[0018] In the above scheme, the throttle inlet pressure stable working condition judgment condition is:

[0019] (1) The engine is running;

[0020] (2) The target air intake volume is stable;

[0021] (3) The actual intake pressure at the throttle outlet is stable;

[0022] (4) The engine speed fluctuation does not exceed the preset range;

[0023] (5) The opening of the boost actuator is equal to its full opening;

[0024] (6) The throttle opening is greater than the preset value;

[0025] (7) The throttle outlet pressure signal is not detected as a fault;

[0026] (8) The product of the engine short-term fuel correction and the long-term fuel correction is within a preset range and exceeds a preset time t2.

[0027] In the above scheme, the method for judging whether the target air intake volume is stable is:

[0028] rho DesFilter (N) = K Rho ×[rho DesRaw (N)-rho DesFilter (N-1)]+rho DesFilter (N-1); where rho DesRaw is the target air intake volume, rho DesRaw (N) is the target intake volume of the Nth sampling period, rho DesFilter is the target intake volume after first-order low-pass filtering, rho DesFilter (N) is the filtered target intake volume of the Nth sampling period, rho DesFilter (N-1) is the filtered target intake volume of the N-1th sampling period, N = 1, 2, 3..., rho DesFilter (0) is equal to the target intake air volume rho at the 0th sampling cycle DesRaw (0); sampling period interval Δt; K Rho is the coefficient, is the preset value: Where n is the engine speed, k Rho is the air volume filter coefficient, which is the preset value;

[0029] in|rho DesRaw (N)-rho DesFilter (N)| <min[rho DesRaw (N), rho DesFilter (N)]×r RhoLim The condition is continuously satisfied for a period of time up to T Rho The latter indicates that the target intake volume is in a stable state. RhoLim is the preset value, T Rho is the default value.

[0030] In the above scheme, the method for judging whether the actual intake pressure at the throttle outlet is stable is:

[0031] p ManFilter (N) = K Man ×[p Man (N)-pManFilter (N-1)]+p ManFilter (N-1); where p Man is the throttle outlet intake pressure, p Man (N) is the throttle outlet intake pressure at the Nth sampling cycle, p ManFilter is the throttle outlet intake pressure after first-order low-pass filtering, p ManFilter (N) is the filtered throttle outlet intake pressure of the Nth sampling period, p ManFilter (N-1) is the filtered throttle outlet intake pressure of the N-1th sampling period, N = 1, 2, 3..., p ManFilter (0) is equal to the throttle outlet intake pressure p at the 0th sampling cycle Man (0); the sampling period interval Δt is the preset value; K Man is the coefficient, is the preset value: Where n is the engine speed, k Man is the throttle outlet intake pressure filter coefficient, which is a preset value;

[0032] In|p Man (N)-p ManFilter (N)| <min[p Man (N), p ManFilter (N)]×r ManLim The condition is continuously satisfied for a period of time up to T Man After that, it means that the intake pressure is in a stable state; among them, r ManLim is the preset value, T Man is the default value.

[0033] In the above solution, the fully open opening degree is the opening degree corresponding to the maximum boosting capacity of the supercharger.

[0034] In the above scheme, the product of the engine short-term fuel correction and the long-term fuel correction is within a preset range and exceeds a preset time t2, wherein the preset range is 0.97-1.03 and the preset time t2 is 5s.

[0035] In the above solution, the engine speed fluctuation does not exceed a preset range, and the preset range is ±15rpm.

[0036] In the above solution, the throttle opening is greater than a preset value, and the preset value is 95%.

[0037] In general, the above technical solutions conceived by the present invention can achieve the following beneficial effects compared with the prior art:

[0038] The present invention provides a method for judging abnormality of an intake system pressure sensor under steady-state conditions. The method strictly and accurately judges pressure abnormality by checking the throttle inlet pressure signal under steady-state conditions of the engine. At the same time, self-learning parameters are continuously updated during the pressure signal verification process, thereby improving the accuracy of subsequent throttle inlet pressure signal verification. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present invention. Also, throughout the accompanying drawings, the same reference figures are used to represent the same components. In the drawings:

[0040] Figure 1 Schematic diagram of the exhaust gas turbocharger engine intake system in the present embodiment.

[0041] Figure 2 Schematic diagram of a flow chart of a method for determining abnormality of an intake system pressure sensor under steady-state conditions in an embodiment of the present invention. DETAILED DESCRIPTION

[0042] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0043] It should be understood that the size of the serial numbers of the steps in the embodiments does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0044] Example 1

[0045] The main components of the exhaust gas turbocharger engine intake system based on the present invention include: atmospheric pressure sensor, supercharger, electronic pressure relief valve, intercooler, throttle pre-temperature pressure sensor, throttle, throttle post-intake temperature pressure sensor, carbon canister solenoid valve, EGR, VVT system, etc. Figure 1As shown. The atmospheric pressure sensor can read the atmospheric pressure and is installed in the PCB board of the controller ECU; the supercharger includes the supercharger body and the exhaust bypass valve, and the boost pressure is controlled by adjusting the opening of the exhaust bypass valve; the electronic pressure relief valve is used to prevent the airflow from oscillating back and forth in the supercharger compressor and opening the pressure relief valve when the engine has a torque reduction request, thereby improving the supercharger surge, thereby increasing the engine life and improving NVH; the pre-throttle temperature and pressure sensor can read the temperature and pressure of the supercharged gas before the throttle; the intercooler is a mechanical part, uncontrolled, located between the supercharger compressor and the throttle, cooling the supercharged gas; the intake temperature and pressure sensor after the throttle can read the temperature and pressure of the supercharged gas before the throttle; the carbon canister solenoid valve is used to introduce fuel vapor into combustion and prevent it from volatilizing into the atmosphere;

[0046] EGR, or exhaust gas recirculation, returns part of the exhaust gas discharged by the engine to the intake manifold and re-enters the cylinder together with the fresh mixed gas; VVT is used to adjust the intake (exhaust) volume, valve opening and closing time, angle, and the amount of air entering the cylinder. The throttle inlet pressure signal verification in the present invention is to verify the rationality of the pressure signal of the pressure sensor before the throttle.

[0047] According to one aspect of the present invention, an embodiment of the present application provides a method for determining abnormality of an intake system pressure sensor under steady-state conditions. Figure 2 ,include:

[0048] When the throttle inlet pressure stable condition judgment condition is met, obtain the average throttle inlet pressure within the preset time t3 Average throttle outlet pressure

[0049] like If the throttle valve inlet pressure signal fails, it is determined that the throttle valve inlet pressure signal fails; otherwise, it is determined that the throttle valve inlet pressure signal does not fail;

[0050] The preset time t3 is 2s in this example, Adpt It is the self-learning correction coefficient, the default value is 0, and it can be saved when the vehicle is powered off.

[0051] Self-learning correction factor r Adpt The method for obtaining is as follows: record the number of times CNT3 that the throttle inlet pressure stable working condition judgment condition is met, and record the number of times CNT3 that the throttle inlet pressure stable working condition judgment condition is met. The number of times CNT4 is recorded after the throttle inlet pressure meets the stable working condition judgment condition The number of times CNT3, CNT4 and CNT5 are updated at most once in each driving cycle of the vehicle;

[0052] If CNT3≥200, CNT4≥160, and CNT5≤10, then r Adpt =r Adpt (z) -0.01;

[0053] If CNT3 ≥ 200, CNT4 ≤ 10, and CNT5 ≥ 130, then r Adpt =r Adpt (z)+0.015;

[0054] In other cases, r Adpt =r Adpt (z);

[0055] where r Adpt (z) is the self-learning correction coefficient of the last update; when CNT3 ≥ 200, the self-learning correction coefficient r Adpt After the update, CNT3, CNT4 and CNT5 are reset to 0, and the counting starts again when the next condition is met.

[0056] In this embodiment, the throttle inlet pressure stable working condition judgment condition is:

[0057] (1) The engine is running;

[0058] (2) The target air intake volume is stable;

[0059] rho DesFilter (N) = K Rho ×[rho DesRaw (N)-rho DesFilter (N-1)]+rho DesFilter (N-1); where rho DesRaw is the target air intake volume, rho DesRaw (N) is the target intake volume of the Nth sampling period, rho DesFilter is the target intake volume after first-order low-pass filtering, rho DesFilter (N) is the filtered target intake volume of the Nth sampling period, rho DesFilter (N-1) is the filtered target intake volume of the N-1th sampling period, N = 1, 2, 3..., rho DesFilter (0) is equal to the target intake air volume rho at the 0th sampling cycle DesRaw (0); Sampling period interval Δt, in this example it is 10ms. K Rho is the coefficient: (This example k Rho The calibrated speed is 1000rpm. The purpose of this setting is to normalize the process. At different speeds, no special calibration is required. Only the k value at 1000 rpm needs to be calibrated.Rho , thereby reducing the calibration test work), where n is the engine speed, k Rho is the air volume filter coefficient, which is 0.02 in this example.

[0060] in|rho DesRaw (N)-rho DesFilter (N)| <min[rho DesRaw (N), rho DesFilter (N)]×r RhoLim The condition is continuously satisfied for a period of time up to T Rho The latter indicates that the target intake volume is in a stable state (the volume fluctuation is small). RhoLim In this example, 0.05 is taken, T Rho In this example, 0.4s is used.

[0061] (3) The actual intake pressure at the throttle outlet is stable;

[0062] p ManFilter (N) = K Man ×[p Man (N)-p ManFilter (N-1)]+p ManFilter (N-1); where p Man is the throttle outlet intake pressure, p Man (N) is the throttle outlet intake pressure at the Nth sampling cycle, p ManFilter is the throttle outlet intake pressure after first-order low-pass filtering, p ManFilter (N) is the filtered throttle outlet intake pressure of the Nth sampling period, p ManFilter (N-1) is the filtered throttle outlet intake pressure of the N-1th sampling period, N = 1, 2, 3..., p ManFilter (0) is equal to the throttle outlet intake pressure p at the 0th sampling cycle Man (0); The sampling period interval Δt in this example is 10ms. K Man is the coefficient: (This example k Man The calibrated speed is 1000rpm. The purpose of this setting is to normalize the process. At different speeds, no special calibration is required. Only the 4-cylinder engine and the speed of 1000rpm k Man , thereby reducing the calibration test work), where n is the engine speed, k Man is the throttle outlet intake pressure filter coefficient, which is 0.02 in this example.

[0063] In|p Man (N)-p ManFilter (N)| <min[p Man(N), p ManFilter (N)]×r ManLim The condition is continuously satisfied for a period of time up to T Man The latter indicates that the intake pressure is in a stable state (the intake pressure fluctuation is small). ManLim In this example, 0.05 is taken, T Man In this example, 0.4s is used.

[0064] (4) The engine speed fluctuation does not exceed a preset range, which in this example is ±15 rpm;

[0065] (5) The opening of the boost actuator is equal to its full opening, which is the opening corresponding to the maximum boosting capacity of the supercharger;

[0066] (6) The throttle opening is greater than a preset value, which is 95% in this example;

[0067] (7) The throttle outlet pressure signal is not detected as a fault;

[0068] (8) The product of the engine short-term fuel correction and the long-term fuel correction is within a preset range (0.97-1.03 in this example) and exceeds a preset time t2 (5s in this example); the acquisition of the short-term fuel correction can be found in the patent "A method and control system for controlling engine short-term fuel correction" with publication number CN113847155A; the acquisition of the long-term fuel correction can be found in the patent "A self-learning method for long-term fuel correction of a gasoline engine" with publication number CN111412074A. If the product of the engine short-term fuel correction and the long-term fuel correction is small, it means that the difference between the engine's requested fuel injection amount and the actual fuel injection amount is small, the engine's requested fuel injection amount calculated based on the intake volume has a higher accuracy, the engine's intake volume has a higher accuracy, and the throttle post-pressure sensor signal is accurate.

[0069] In summary, the present invention provides a method for determining an abnormality of an intake system pressure sensor under steady-state conditions. The method can identify whether a pressure signal is abnormal under steady-state conditions, thereby providing an early warning to avoid damage to the engine and personal safety due to abnormal engine control.

[0070] It should be pointed out that, according to the needs of implementation, the various steps described in this application can be divided into more steps, or two or more steps or partial operations of the steps can be combined into a new step to achieve the purpose of the present invention.

[0071] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for determining abnormality of an intake system pressure sensor under steady-state conditions, characterized in that: include: When the throttle inlet pressure stable working condition judgment condition is met, the average value of the throttle inlet pressure and the average value of the throttle outlet pressure within a preset time are obtained; Whether a throttle inlet pressure signal fails is determined based on the throttle inlet pressure average value, the throttle outlet pressure average value and a self-learning correction coefficient.

2. The method for determining abnormality of an intake system pressure sensor under steady-state conditions according to claim 1, characterized in that: The specific method to determine whether the throttle inlet pressure signal is faulty is: When the throttle inlet pressure stable condition judgment condition is met, obtain the average throttle inlet pressure within the preset time t3 Average throttle outlet pressure like If the throttle valve inlet pressure signal fails, it is determined that the throttle valve inlet pressure signal fails; otherwise, it is determined that the throttle valve inlet pressure signal does not fail; Wherein the Adpt It is the self-learning correction coefficient, the default value is 0, and it can be saved when the vehicle is powered off.

3. The method for determining abnormality of an intake system pressure sensor under steady-state conditions according to claim 2, characterized in that: The self-learning correction coefficient r Adpt The method for obtaining is as follows: record the number of times CNT3 that the throttle inlet pressure stable working condition judgment condition is met, and record the number of times CNT3 that the throttle inlet pressure stable working condition judgment condition is met. The number of times CNT4 is recorded after the throttle inlet pressure meets the stable working condition judgment condition The number of times CNT3, CNT4 and CNT5 are updated at most once in each driving cycle of the vehicle; If CNT3≥200, CNT4≥160, and CNT5≤10, then r Adpt =r Adpt (z) -0.01; If CNT3 ≥ 200, CNT4 ≤ 10, and CNT5 ≥ 130, then r Adpt =r Adpt (z)+0.015; In other cases, Adpt =r Adpt (z); where r Adpt (z) is the self-learning correction coefficient of the last update; when CNT3 ≥ 200, then the self-learning correction coefficient r Adpt After the update, CNT3, CNT4 and CNT5 are reset to 0, and the counting starts again when the next condition is met.

4. The method for determining abnormality of an intake system pressure sensor under steady-state conditions according to claim 1, characterized in that: The throttle inlet pressure stable working condition judgment condition is: (1) The engine is running; (2) The target air intake volume is stable; (3) The actual intake pressure at the throttle outlet is stable; (4) The engine speed fluctuation does not exceed the preset range; (5) The opening of the boost actuator is equal to its full opening; (6) The throttle opening is greater than the preset value; (7) The throttle outlet pressure signal is not detected as a fault; (8) The product of the engine short-term fuel correction and the long-term fuel correction is within a preset range and exceeds a preset time.

5. The method for determining abnormality of an intake system pressure sensor under steady-state conditions according to claim 4, characterized in that: The method for judging whether the target air intake volume is stable is: rho DesFilter (N) = K Rho ×[rho DesRaw (N)-rho DesFilter (N-1)]+rho DesFilter (N-1); where rho DesRaw is the target air intake volume, rho DesRaw (N) is the target intake volume of the Nth sampling period, rho DesFilter is the target intake volume after first-order low-pass filtering, rho DesFilter (N) is the filtered target intake volume of the Nth sampling period, rho DesFilter (N-1) is the filtered target intake volume of the N-1th sampling period, N = 1, 2, 3..., rho DesFilter (0) is equal to the target intake air volume rho at the 0th sampling cycle DesRaw (0); sampling period interval Δt; K Rho is the coefficient, is the preset value: Where n is the engine speed, k Rho is the air volume filter coefficient, which is the preset value; in|rho DesRaw (N)-rho DesFilter (N)| <min[rho DesRaw (N), rho DesFilter (N)]×r RhoLim The condition is continuously satisfied for a period of time up to T Rho The latter indicates that the target intake volume is in a stable state. RhoLim is the preset value, T Rho is the default value.

6. The method for determining abnormality of an intake system pressure sensor under steady-state conditions according to claim 4, characterized in that: The method to determine whether the actual intake pressure at the throttle outlet is stable is: p ManFilter (N) = K Man ×[p Man (N)-p ManFilter (N-1)]+p ManFilter (N-1); where p Man is the throttle outlet intake pressure, p Man (N) is the throttle outlet intake pressure at the Nth sampling cycle, p ManFilter is the throttle outlet intake pressure after first-order low-pass filtering, p ManFilter (N) is the filtered throttle outlet intake pressure of the Nth sampling period, p ManFilter (N-1) is the filtered throttle outlet intake pressure of the N-1th sampling period, N = 1, 2, 3..., p ManFilter (0) is equal to the throttle outlet intake pressure p at the 0th sampling cycle Man (0); the sampling period interval Δt is the preset value; K Man is the coefficient, is the preset value: Where n is the engine speed, k Man is the throttle outlet intake pressure filter coefficient, which is a preset value; In|p Man (N)-p ManFilter (N)| <min[p Man (N), p ManFilter (N)]×r ManLim The condition is continuously satisfied for a period of time up to T Man After that, it means that the intake pressure is in a stable state; among them, r ManLim is the preset value, T Man is the default value.

7. The method for determining abnormality of an intake system pressure sensor under steady-state conditions according to claim 1, characterized in that: The fully open opening degree is the opening degree corresponding to when the supercharger has the maximum supercharging capacity.

8. The method for determining abnormality of an intake system pressure sensor under steady-state conditions according to claim 1, characterized in that: The product of the engine short-term fuel correction and the long-term fuel correction is within a preset range and exceeds a preset time t2, wherein the preset range is 0.97-1.03 and the preset time t2 is 5s.

9. The method for determining abnormality of an intake system pressure sensor under steady-state conditions according to claim 1, characterized in that: The engine speed fluctuation does not exceed a preset range, and the preset range is ±15 rpm.

10. The method for determining abnormality of an intake system pressure sensor under steady-state conditions according to claim 1, characterized in that: The throttle opening is greater than a preset value, and the preset value is 95%.

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